Condensation products of the dihydrobenzimidazole type



Patented July 29, 1952 CONDENSATION PRODUCTS OF THE DIHYDROBENZIMIDAZOLE TYPE Robert C. Gunther, G'alesburg, Ill., assignor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application March 21, 1950,

Serial No. 151,053

7 Claims. 1

This invention relates to new condensation products of the dihydrobenzimidazole type which are particularly useful as additives to 2,4-diamino-aniline developers.

It is known that azine dyestuii images in exposed silver halide emulsions are produced by color developing silver halide emulsions with 'ZA-diamino-aniline developing agents in the presence of color formers. The procedure of this process is described in United States Patent 2,486,440, granted on November 1, 1949.

The azine dyes produced in this way have unusual stability and superior spectral characteristics, particularly when compared with the quinonimine or azomethine dyes produced with developers of the p-phenylenediamine type.

Despite the many recognized advantages of this new class of color developers, they possess .two disadvantages which provide a somewhat serious problem in the use of the azine method. The first disadvantage occurs in the development of multilayer film and is manifested by a loss of color rendition in the azine images formed in such material.

Such loss of color rendition has been found to be attributable to a phenomenon peculiar to the aforementioned azine processing which is characterized herein as proximity development. The following explanation of such phenomenon will serve to give a better understanding of the bjects of he pr s nt invention.

As is known, the conventional material employed at the present time in color photography is an integral tripack consisting essentially of three superimposed silver halide emulsion lays ers, the bottom layer being sensitized to red, the middle layer to green, and the top layer to blue. When such a tripack is exposed, the red densities of the picture are recorded in the bottom layer, the green densities in the middle layer, and the blue densities in the top layer. According to customary practice, the image formed in the respective layers is complementary in color to the light rays for which the particular layer is sensitized.

One of the best modes of constructing such tripacks involves the utilization in each of the three silver halide emulsion layers of a color former which is rendered non-diffusing in the emulsions. Where such tripacks are of the reversible type, they are processed by developing first in a black and white developer, and finally in a color forming developer.

In the color development of such a tripack with a 2,4-diamino-aniline, the color developer reduces in any one layer the silver halide remaining after the first development and is itself oxidized to an active state capable of coupling with the color former present in that layer to form a positive dye image. Consequently, in anyone layer the amount of dye produced will be a func-, tion of the amount of residual silver halide; in that layer and the resulting dye will be formed imagewise. Thus, in each of the three layers of the tripack, one of the primary color densities (blue in the top layer, green in the middle layer, and red in the bottom layer) is accurately re corded in the form of a positive complementary dye image.

The coupling reaction between the migratory oxidized developer and the immobilecolor formerin each layer is normally rapid so that the oxidized developer travels only a very short distance before encountering the color former molecule and coupling therewith. It often happens,- however, that some dye may be produced in a particular layer by the coupling of a color. former in that layer with an oxidized developermolecule that originated not in that particular layer but in one of the adjacent layers. Typically, an oxidized developer molecule originating in the red-sensitive layer may escape from this layer without coupling and migrate to the greensensitive layer to couple with the color former molecule in that layer. As a result, there will be produced in the green-sensitive layer a certain amount of magenta dye which records not the green densities of the original picture, but red densities which should have been confined to the bottom 01' red-sensitive layer. This migration of oxidized developer from one layer to an adjacent layer is the phenomenon known as proximity development.

The other disadvantage also occurs in the development of multilayer film and is manifested by the inability of the first (black and white) developing agent to reduce the slightly activated silver in the highlight or white portions of'the veloping agents and also suppress proximity .de-

velopment in the azine procedure while utilizing 2,4-diamino-anilines for color development.

Other objects and advantages of this invention will become apparent by reference to the following specification in which its preferred details and embodiments are described.

The above objects are accomplished by condensing a 2,4-diamino-aniline with either a lower alkyl a-ketocarboxylic acid or lower alkyl aldehyde. In carrying out the condensation reaction 1 part of a 2,4-diamino aniline is suspended in a mixture of 2.5 parts of a lower boiling alcohol, such as methyl, ethyl, isopropyl and the like, in 1 part of 3N hydrochloric acid solution. To this mixture 3 parts of either a lower alkyl a-ketocarboxylic, acid or lower alkyl aldehyde are added and the whole warmed on a steam bath to 40- 50., C. until the solution of the 2,4-diaminoaniline is completed. This usually takes about to minutes. The clear, amber-coloredssolution is treated with decolorizing carbon and filtered. The hot filtrate is diluted with 3 parts of alcohol and cooled in an ice bath. The product, which separates as pink to colorless crystals, is collected on a Buchner funnel, washed with alcohol,,and dried. The yield of the final product is in the range of -70%.

Although the exact composition of the reaction product has not been definitely established, it is believed, to be of the dihydrobenzimidazole type. The formation of such a compound might be postulated on the basis of the following reaction while utilizing 4- (p-hydroxyethylamino) eS-phenylamino-metanilic acid as the 2,4-diamino-aniline and (1) B-methyl-pyruvio acid as the lower alkyl a-kGtOCELIbOXYliO acid, and (2) propionaldehyde as the aldehyde:

1) I O E nose-- CHSCHZCHO NHCHzCHzOH l NH:

ITIHCeH;

Hotsz0 NCH2CH2OH HN-(|]H CHzCHa (2) I "NHCeHt v +CH3CHCOCOOH NHCH2CH10H IITHOeH The reaction products, prepared in accordance with the foregoing procedure are added to azine color developers that are used for the development of difiusion where the color forming component is in solution in the color developer, or development of emulsions containing non-diffusing color formers, and development by either reversal ornegative processing procedures.

The 2,4-diamino-ani1ines which are employed as the color developers and for the preparation of the condensation product, by treatment with a lower alkyl a-ketocarboxylic acid or with lower alkylaldehyde, are of the type described in the aforementioned Patent 2,486,440 and characterized by the following formulae:

IIIRqR Y NHRs and II TRiR1 wherein R1 is hydrogen or an aliphatic radical, such as alkyl, 1. e., methyl, ethyl, propyl, butyl, amyl, and the like, carboxyalkyl, such as carboxymethyl, carboxyethyl, carboxybutyl, and the like, hydroxyalkyl, such as hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, and the like, sulfoalkyl, such as sulfomethyl, sulfopropyl, sulfobutyl, and the like, R2 is aliphatic as above, or an aromatic radical, such as aryl, i. e., phenyl, naphthyl, and the like, carboxyaryl, i. e., carboxyphenyl, carboxynaphthyl, and the like, sulfoaryl, such as sulfophenyl, sulfonaphthyl, and the like, alkoxyaryl, such as methoxyphenyl, methoxynaphthyl, ethoxyphenyl, butyroxyphenyl, and the like, alkylaryl, such as toluyl, ethylphenyl, propylphenyl, and the like, heterocyclic, such as 2-pyridyl, Z-piperidyl, 2-indo1yl, 2-quinolyl, and the like, R3 is an aromatic or aliphatic radical as illustrated above, Q represents th atoms necessary to complete a six-membered isocyclic ring system, such as benzo and the like, and Z and Y are hydrogen, sulfo, or carboxy.

The lower alkyl a-ketocarboxylic acids and lower alkyl aldehydes, which are treated with the 2,4-diamino-aniline to form the condensation product are those of the following formulae:

R4CHO and R5COCOOH wherein R4 is hydrogen or a lower alkyl, such as methyl, ethyl, propyl, butyl, isobutyl, amyl,

and the like, and R5 is a lower alkyl of the same value as R4.

Specific examples of such lower alkyl 11- ketocarboxylic acids and aldehydes are:

Specific examples. of 2,4-Tdiamino-anilines are:

- (methylphenylaminod Color formers to be used with the aforementioned developers to give yellow azine dye images are also described in application Serial No. 101,913, filed June 28, 1949, now Patent No. 2,570,116. These compounds are typified by the fact that they are open chain ketomethylene compounds. Examples of such compounds are:

Acetoacetanilide N-l-naphthylacetoacetamide N,N-ethylenebisacetoacetamide p,p'-Bi-o-acetoacetaniside N-2-naphthylbenzoylacetamide p,p'-bi-acetoacetanilide a,a-Terephthaloylbis- (3-chloro-4,6 dimethoxyacetanilide) a-BGDZOYIELCBtaDiIidE.

Preferably, the color formers utilized contain a group rendering them non-migratory in. the emulsion. Examples of such compounds are: 2-(m-benzoylacetamidophenyl) -1 octadecyl 5- benzimi'dazolesulfonic acid 3,3 ureylenebis 5 p-benzoylacetamidobenzamide-benzenesulfonic acid 2 p benzoylacetamidobenzamido 6 stearoylamino-p-toluenesulfonic acid 2 (p-benzoylacetamidophenyl) -l octadecyl 5- benzimidazolesulfonic acid p-Cyanoacetyl-3-octadecenylsuccina1ic acid.

Color formers capable. of producing magenta dyestuff images are also described. in application Serial No. 101,913, filed June 28., 1949, as. well as in application Serial No. 793,533, filed December 23, 1947, now Patent No. 2,524,741. Preferably, these color formers are 6-halogen-8-hydroxyquinolines, and. particularly those which are-nonmigratory in the emulsions. Examples of-the latter type compounds are:

6-stearoylamino-2-(2phenyl-6'-bromo 8 hydrox-y-cinchoninoyl) -am-inotoluene-;4 sulionic acid 2-phenyl-6 chloro 8' hydroxy cinchoninoyloctadecyl taurine 6-decoxy-3- (2-phenyl-6-bromo8 hydroxy tzcinchoninoyl) -aminobenzenesulfonic. acid 2-(3 stearoylaminophenyl) 6 bromo..-';8l-'hy-* droxy-cinchonini'c acid 2-stearoylamino6-(fi-chloro 8 -:hydroxy cinchoni-noyl)v -amino-toluene-4.-.snfonic acid, and:

the like. J

6. formers iorthe cyan: image. are also described in application .Serial N o; 101 ,913,;and in United States Patent.2;445;25.2, granted-July 13,

1948. Preferably, these. colorformers are aryl-- J acid .derivatiyes, particularly' those containing a group rendering-the color former non-migratory in the emulsion. Examples of therlatter compounds are:

Dodecyl urethane of B-sulfoethyl-J-acid Tetradecyl urethane of p-anisy1J-acid 2-hexadecyl urethane of phenyl-J -acid1 4-stearoylaminophenyl-J-acid,' and the like.

The. following, examples describe in detail methods. for accomplishing the. above objects, but itis to. be. understood that, they are inserted merely for purposes of illustration and are not to. lee-construed as limiting the. scope oi the invention. All parts. are. by weight unless otherwise specified.

EXAMPLE I Reaction. product from 4-(fl-hydromyethylamino) -6-phenylamino-metanilic acid and pyruvz'c acid j One part of 4 (,c-hydroxyethylaminm-fiphenylaminoemetanilic acid was suspended in a mixture of 2.5 parts of ethyl alcohol and 1 part of 3N hydrochloric acid solution. To this mixture 3 parts of pyruvic acid were added and the whole warmed on a steam bath to 40-50 C. for 10 to .15 minutes. The clear, amber-colored solution was treated with. the decolorizing carbon and filtered. The hot fi1trate"-1-was dilutedwith 3 parts of ethyl .alcohol and cooled in an ice bath. The product which separated aspink to colorless crystals was collected on a Buchner funnel, washed with ethyl alcohol, and dried. The yield of the product is 65%.

EXAMPLE II.

Reaction product from '4-(shydroryethylamino) -6-phenyZamino-metanilic acid and ethyl pym'vic aczld Example I was repeated with the exception that '3 parts of pyruvic acid were replaced by 3.2 partsof B-ethyl pyruvic acid. The product, whichv separated as almost colorless crystals, was collected on a Buchner funnel, washed with methanol, and dried. The yield of the product is EXAMPLE III EXAMPLE IV Reaction, product i from 4-methylamino-6- phenyla'm'i'mo-metdnilic acid and propz'onaldehyde One part of 4-methylamino-6-phenylamin0- metanilic acid was suspended in a mixture of 2.5 parts of methanol and 1 part of 3N hydrochloric acid solution. To this mixture Was added 3 parts of propionaldehyde and the whole warmed on a steam bath to 40-50 C. for 10 to 15 minutes until the solution of the 4-methylamino-6-phenylamino-metanilic acid was completed. The clear solution was treated with the decolorizing carbon and filtered. The hot filtrate was diluted with 3 parts of methanol and cooled in an ice bath. The product, which separated as slightly pink crystals, was collected, washed with methanol, and dried. The yield of the product'is 64.5%.

EXAMPLE v Reaction product from 4 (,3 hydroxyethylamino)-6-phenyZamino-metanilic acid and 3- methyZ-pymvic acid Pink to colorless crystals were obtained when 1 part of l-(e-hydroxyethylamino)-6-phenylamino-metanilic acid was condensed with 3 parts of 3-methyl-pyruvic acid following the procedure of ExampleIV.

The following examples describe in detail the utilization of the foregoin condensation products as energizers for 2,4-diamino-aniline developing agents and the suppression of proximity development in the azine procedure while utilizing 2,4-diamino-am'lines for color development.

EXAMPLE VI p-Monomethylamino phenol sulfate 2 Sodium sulfite 20 Hydroquinone 4 Sodium carbonate 80 Sodium thiocyanate 5 Potassium bromide 4 Water to make 1000 cc.

The developed film was shortstopped for 3 minutes in a 3% aqueous solution of acetic acid, re exposed, and color developed for minutes at 68, F. in a developer of the following composition: I

' Grams 4- (fi-hydroxyethylamino) 6 allyl aminometanilic acid 6 Sodium carbonate, monohydrate 40 Sodium sulfite 60 Potassium bromide 7.5

Pyridine 12 Reaction product from 4-( 8-hydroxyethylamino) -6-phenylamino-metanilie acid and pyruvic acid (Example I) 3 Water to make 1000 cc.

After development, the color developed film was bleached in a ferricyanide bleach bath, fixed in an acid hardening hypo bath, and bathed for a few minutes in a bicarbonate-formaldehyde hardening bath.

After drying, the film showed much better color rendition and cleaner whites. In fact, the blue, greens, and reds of the film were substantially more brilliant than those in the same film developed in the same color developer but not containing the reaction product from l-meth- .ylamino-6-phenylamino-metanilic acid and pyruvic acid.

EXAMPLE VIE A developer solution of the following composition was prepared:

Grams 4- (,3 hydroxyethylamino) -6'-phenylaminometanilic acid 5 Sodium carbonate, monohydrate 50 Sodium sulfite 50 Potassium bromide 4.5 Benzylamine 10 Reaction product from 4-(5-hydroxyethylamino) 6 phenylamino metanilic acid and fi-ethyl-pyruvic acid (Example H) Water to make 1000 cc.

An integral tripack composed of a red-sensitive bottom layer containing a cyan color former,

H H 033 N COCU Ja SOaH A green-sensitive middle layer containing a magenta color former,

and a blue-sensitive top layer containing a yellow color former,

H O0 0 0112s ONHG-C ONH NCOCnHas was exposed, the latent image developed in a black and white developer as in Example VI, reexposed, and then developed for 15 minutes in the above developer solution.

After development, the film was washed, bleached in ferricyanide bleach, and fixed in an acid hardening hypo solution.

As a result, there was obtained a multicolor positive (cyan dye in bottom, magenta in middle, and yellow in top) of exceptional clarity and brilliance, with unusually clean whites.

EXAMPLE VIII An integral tripack with a bottom layer composed of a red-sensitive emulsion containing phenyl-J-acid-octadecyl urethane, a middle layer composed of a green-sensitive emulsion containing 2-stearoylamino-6-(8 hydroxy-cinchoninoylamino)-toluene-4-sulfonic acid, and a top layer composed of a blue-sensitive emulsion containing 2 (4 benzoylacetaminophenyl) -l octadecyl-5-benzimidazole sulfonic acid was ex posed and the latent image developed in a black and white developer, re-exposed, and the residual silver halide developed in a solution of the following composition:

4 Grams 4-(5 hydroxyethylamino) 6 phenylaminometanilic acid 5 Sodium carbonate, monohydrate 40 Sodium sulfite 60 Potassium bromide 5 Pyridine 16 Benzylamine 1 EXAMPLE IX Example VII was repeated with the exception. that the reaction product from 4-(B-hydroxyethylamino)-6-pheny1amino-metanilic acid and B-ethyl-pyruvic acid was replaced by the samev quantity of the reaction product from 4-methy1- amino-6-phenylaminometanilic acid and acetaldehyde.

EXAMPLE X Example VIII was repeated with the exception that the reaction product from 4-methylamino- B-phenylamino-metanilic acid and propionaldehyde was replaced by 3 grams the reaction product from 4-(B-hydroxyethylamino)6-phenylamino-metanilic acid and B-methyl-pyruvic acid.

I claim:

1. A condensation reaction product of the dihydrobenzimidazole type obtained by heating to above room temperature a 2,4-diamino-aniline in which the nitrogen atom of the 2-amino group is substituted by at least one hydrogen atom and a member selected from the class consisting of a lower alkyl a-ketocarboxylic acid and a lower alkyl aldehyde for a period of time until solution of the 2,4-diamino-aniline is completed, then cooling and separating the condensation reaction product.

2. A condensation reaction product of the dihydrobenzimidazole type identical with that obtained by treating an aromatic triamine selected from the class consisting of those of the following formulae:

NH R:

and

man,

in which R1 is selected from the class consisting of hydrogen and lower acyclic aliphatic radicals, R2 is selected from the class consisting of lower acyclic aliphatic radicals, monocyclic and bicyclic carbocyclic aromatic radicals, and Z-pyridyl, 2- piperidyl, 2-indolyl, and 2-quino1yl radials, R3 is selected from the group consisting of lower acyclic aliphatic radicals, and monocyclic and bicyclic carbooyclic aromatic radicals, X and Y are selected from the class consisting of hydrogen, sulfo, and carboxy, and Q represents the atoms necessary to complete a 6-membered isocyclic ring system, with a compound selected from the class consisting of the following formulae:

R4CHO and RsCOCOOH wherein R4 is selected from the class consisting of hydrogen and lower alkyl, and R5 is lower alkyl, for a period of time until the solution of the aromatic triamine is completed, then cooling and separating the condensation reaction product.

3. A condensation reaction product according to claim 1, in which the product is that from 41- (yS-hydroxyethylamino) -.6-phenylamino-metanilic acid and pyruvic acid.

4. A condensation reaction product according to claim 1, in which the product is that from 4- (p-hydroxyethylamino) 6 phenylamino -1metanilic acid and acetaldehyde.

5. A condensation reaction product according to claim 1, in which the product is that from 4- methylamino-6-phenylamino-metanilic acid and propionaldehyde.

6. A condensation reaction product according to claim 1, in which the product is that from 4- methylamino-6-phenylamino-metanilic acid and B-ethyl-pyruvic acid.

7. A condensation reaction product according to claim 1, in which the product is that from 4- (B-hydroxyethylamino) 6 phenylamino metanilic acid and 3-methy1-pyruvic acid.

ROBERT C. GUNTHER.

No references cited. 

2. A CONDENSATION REACTION PRODUCT OF THE DIHYDROBENZIMIDAZOLE TYPE IDENTICAL WITH THAT OBTAINED BY TREATING AN AROMATIC TRIAMINE SELECTED FROM THE CLASS CONSISTING OF THOSE OF THE FOLLOWING FORMULAE: 